With reference to FIG. 1, a conventional gold bump structure 10 is formed on a silicone substrate 20, mentioned silicone substrate 20 comprises a plurality of bond pads 21 and a protecting layer 22, wherein a plurality of openings 23 are formed on the protecting layer 22, and the openings 23 reveal the bond pads 21. The gold bump structure 10 comprises an under bump metallurgy layer 11 and a gold bump layer 12, the under bump metallurgy layer 11 is formed on the bond pads 21, and the gold bump layer 12 is formed on the under bump metallurgy layer 11. When the gold bump structure 10 is eutecticly bonded with one contact (such as connection pad or pin) of the other electronic device, the contact area between the gold bump structure 10 and the contact is insufficient to degrade coupling strength between the gold bump structure 10 and the contact. In addition, a displacement phenomenon occurred in the process of coupling the contact and the gold bump structure 10 may cause a short condition between adjacent contacts. Besides, the gold bump structure 10 is composed of the gold bump layer 12 and leads a higher production cost.